DAKAR, Senegal — Two United Nations investigators and their Congolese interpreter have been found dead two weeks after going missing in the Democratic Republic of Congo, the Congolese government said on Tuesday.

Villagers on Monday stumbled on the bodies of US citizen Michael Sharp, Swedish national Zaida Catalan, and Congolese translator Betu Tshintela in a shallow grave in Kasai Central, a province some 1,700 kilometers from the capital, Kinshasa. The two UN experts had been monitoring sanctions imposed on the central African country by the UN Security Council.

Accompanied by Tshintela, Sharp and Catalan had spent two weeks in Kasai investigating reports of rights abuses after local rebels took up arms against the government in recent months. They were criss-crossing the town on motorbikes when they were snatched on a bridge on March 13, Congolese Communications Minister Lambert Mende said at the time. The three Congolese motorbike drivers also disappeared alongside them — the identity of their captors remains unconfirmed.

Monusco, the UN peacekeeping mission based in the country, deployed "Uruguayan peacekeepers and Tanzanian special forces on a search and rescue operation for the missing people," but to no avail. According to Human Rights Watch, it was the first time UN workers had ever been reported missing in the country.

A Congolese government spokesperson said Tuesday the bodies had been identified. "It is the two investigators. We identified the third body in the grave with them as their Congolese interpreter," Mende told Reuters.

Sharp’s father, John, a professor at Hesston College, posted on his Facebook page on Tuesday that the bodies were being identified using dental records and DNA samples. “This is a message I hoped never to write. Since no other Caucasians have been reported missing in that region, there is a high probability that these are the bodies of MJ and Zaida,” he wrote.

Tributes poured in beneath the post from friends, colleagues, and Congolese sympathizers. The US State Department did not immediately respond to a request for comment from BuzzFeed News.

US Ambassador to the United Nations Nikki Haley offered her "prayers and heartfelt condolences" to Sharp and Catalan's families in a statement released Tuesday evening. "It is always difficult to lose a brave American dedicated to service," her statement continued. "Michael was working on the front lines of what we try to do at the United Nations every day: find problems and fix them. He selflessly put himself in harm’s way to try to make a difference in the lives of the Congolese people. His courage and desire to serve others is an example for us all."

The DRC is home to multiple militias competing for stakes in the nation's rich mineral resources, and hundreds of civilians have been killed in the violent conflict in recent months. But the central region of the country, where Kasai Central is located, has been relatively peaceful compared with the east, which borders Rwanda and Burundi.

Sharp had been working with militia groups in DRC for several years, according to local newspapers, including helping to negotiate the release of child soldiers while working as a missionary for the Mennonite Central Committee.

President Joseph Kabila triggered the latest wave of violence after he refused to step down when his presidential mandate expired in December, saying a lengthy voter registration process needed to take place. Since then, rebels in Kasai Central known as Kamuina Nsapu have rejected the central government’s authority, which is often shaky across the country, the second-largest in Africa.

Some 40 police officers were found executed in the region over the weekend. But Kamuina Nsapu’s exact motives haven’t always been clear, as they have also allegedly used the conflict to settle ethnic scores, including attacks on civilians in schools and churches.

Government soldiers, armed with machine guns, have confronted the militia, who in contrast are typically armed with machetes and homemade rifles, but have yet to force the rebels to stand down. The UN’s peacekeeping mission in Congo said it had informed the government of 10 mass grave sites in or around the region since December. Congolese forces are also suspected to have killed 84 militia members in February, the UN told journalists in Kinshasa this month.

“It was confirmed to us that two bodies had been found but there has not yet been confirmation of the identities of those bodies. So we have decided not to say anything unless and until that step happens and in the meantime of course our thoughts are with the families of those missing," Matthew Rycroft, the United Kingdom’s UN ambassador, who currently holds the rotating presidency of the Security Council, said in a statement on Tuesday.

Monica Mark is the West Africa Correspondent for BuzzFeed News and is based in Dakar, Senegal.